Current production vehicles utilize hinges and gas springs for pivotally supporting and counterbalancing rear lift gates during movement between open and closed positions. Adjacent the closed position of the lift gate, the extending bias of the gas springs utilized to provide the counterbalancing does not always assist in the opening movement of the lift gate due to the positioning of the gas springs so as to be capable of providing sufficient counterbalancing in the open position where the counterbalancing torque required is much greater. The lack of any assist in the opening near the closed position is more of a problem with larger lift gates which is the tendency toward which lift gates are moving in current production vehicles.
Prior to the use of gas springs, vehicle closure members were previously counterbalanced by torque rods such as disclosed by U.S. Pat. Nos: 2,947,025 Campbell et al.; 3,339,969 Bridle et al.; 4,291,501 Steinberg et al.; and 5,358,301 Konchan et al. Other closure members that utilize torque rod counterbalancing are disclosed by U.S. Pat. Nos.: 3,389,423 Johnson; 3,498,207 Hazen; 4,949,426 Komaki; and Re. 32,878 Leonard.